"I've played enough footy to realise now that it's my fault that my technique was wrong in that circumstance," Sims told AAP.

The emotional exit of skipper and popular Novocastrian Kurt Gidley has left a gaping hole in seniority in the Hunter, an important figure that new coach Nathan Brown has yet to appoint.

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But it's the departure of fellow back-row hitman Beau Scott that has emboldened Sims to change his ways.

"I describe myself as a leader of sorts, and some senior players have to put their hand up and fill those roles," he said.

"If we could play forever, it'd be great. But your days are always numbered."

That realisation has dawned quickly on the former North Queensland forward, who has sobered in the understanding that he now walks the thinnest of tightropes with the match review committee.

Any more trouble with his tackling technique is more than likely to see him shelved for a longer period.

"I have to put my hand up and cop it on the chin, make sure I serve my time, and come back and be as clean as possible because the littlest of trouble I get in, it backs up with my loading," he said.

"I've got to keep as clean as I can."

The 25-year-old NSW Origin hopeful says the appointment of defensive specialist coach Mark Andrews from St George-Illawarra, as well as development mentor Craig Smith, has helped to eradicate his bad habits.

"I'm working with our new trainer `Bumper' (Andrews) and Smithy, our contact coaches, especially under fatigue, tackling, diving and picking my shots when I can and can't bend," Sims said.

After initially feeling frustrated with the governing body for changing their shoulder charge rules mid-season, Sims admits he now has to move with the times.

"As much as you want to kick and scream about it, there's no point doing it because they're not going to change it back to the old rules," he said.

"You have to adapt to the changes that the game's making, otherwise you'll find yourself behind if you don't."